Air cooled engine cylinder



May 23, 1933. 1R. CHILTON '71,910,591

v AIR COOLED ENGINE CYLINDER Filed Aug. 7, 1931 vlatented May 23, 1933 VUNITED STATES PATENT OFFICE ROLAND cEiL'rON, or RIDGEWOOD, NEW JERSEY,AssrGNoR 'ro WRIGHT AERONAUTI- cAL CORPORATION, A CORPORATION OE NEWYORK `AIB. COOLED ENGINE CYLINDER Application filed August 7, 1931.Serial No. 555,674.

-My invention relates to air-cooled engines and more particularly toimprovements in the cylinder head construction thereof.

At the points of mostintense heat low such 5 as the spark pluglocations, there is in conventional designs of air-cooled aircraftengines, insuilicient area on which to base the desired amount offinning close to the spark plugs, so that cooling is largely dependenton conduction ofthe heat into the surrounding area of the-'cylinderhead.. wall. Also, in air-cooled aircraft engines, the fins areinterrupted at the spark plug Openings, to aii'ord wrench room aroundthe spark plugs, where` by the conductivity of heat is prejudiced andthe fin area at these critical points reduced.

The object of the present invention is to provide a finning arrangementwhich will lafford improved air low at the rear of the cylinder headwall and will at the same time augment the cooling of the cylinder headin the hot spot Zone of the one or more spark plug locations. Thatthismay beV satisfactorily accomplished, the cylinder head wall isprovided with hollow integral cylindrical extensions surrounding andcoextensive with the spark plugs, and the cylinder coolinglindisposition is such that certain of the fins are 3`0 extendeduninterruptedly from the cylinder head wall along the spark plug coolingextensions. In this way a very rsubstantial increase in the areawithdrawing heat from the cylinder head wall near the spark plugs f isprovided. At the same time the reorganized fin disposition provides goodair ow along the fins and to the spark plug extension at the back of thecylinder head by three distinct paths of flow, i. e., over the top 3fand around each side of the engine cyliner. e

In the drawing z` Fig. 1 is a rear view of a cylinder head showing thepreferred inning arrangement, and

Fig. 2 is a section on the line 2--2 oi Fig. 1. In the embodiment of theinvention selected for illustration the wall of the cylinder head isindicated at 10. It is of more or less conventional design. Formedtherein is the usual inlet port 12 and exhaust port 14,

and integral therewith are suitable rocker box housings 16 and 18. Frontand rear spark plugs are designated as 20 and 22 respectively and eachis surrounded by a cylindrical wall 24 integral with the cylinder walland extending olil therefrom substantially to the outer ends of thespark plugs. Suitable caps 26 may be provided to connect the spark plugcables (not shown) to the spark plugs 20 and 22, and these caps may bedesigned to give radio shielding similar to that described in the`co-pending application of R. F. Gagg, Serial Number 472,040,l filedJuly 31, 1930, and assigned to the assignee herein.

0n the top of the cylinder head a plurality of so-called pompadour insare provided. 'Ihese fins 28 are vertical ns and they extenduninterruptedly across the top of the cylinder head between the rockerbox housings 16 and 18. rIhe cylinder head has also formed thereon aplurality of horizontally extending'circumferential fins 30, the upperof which, designated as 30', merge into the successive pompadour fins28. The pompadour fins and the circumferential fins which subtend `thewidth of the spark plug cooling` extensions 24 are carried along saidextensions uninterruptedly to points at or near their outer ends (seeFig. 2). By thus arranging the fins 28, 30 and 30 an easy path of airlow between the fins over the top of and around both sides of thecylinder head to the spark plug cooling extensions 24 is provided.Moreover, the spark plug cooling extensions, in and of themselves,afford an eliective conductive path to the additional iinning extendinglongitudinally thereof, Vand the added linnin per se provides additionalcross-sectiona area in the path of heat flow. It may also be pointed outthat the merging of the pom adour fins withthe upper circumferential I ssubstantially symmetrical with respect to the ports 12 and 14, gives ashape lconducive to easy air iow around and back ofthe rocker boxhousings which usually interfere lwith the air ow in conventional inningsystems. No interruption of the cooling fins at the juncture of thespark plug cooling extensions 24 and the cylinder Wall 10 exists. Boththe pompadour fins and the circumferential fins y which subtend thewidth of the spark plug extensions, extend without a break in thecontinuity of theo fins for substantially the full length of therespective extensions. In other words, the cylinder wall and its coolingfins are integral with the cooling extensions and the cooling fins withwhich said extensions are provided.

For convenience of descri tion the invention has been described witspecific refer'- ence to the cooling of the hot spots generated aroundthe spark plugs. Obviously the invention can be applied to any other;vpoint on the cylinder head where additional cooling is desirable. Tomention one instance only, compression ignition engines have aninjection valve which could be substituted for one of the spark plugsillustrated without departin from the spirit of the invention.

at I claim is:

1. In an air cooled internal combustion engine; a cylinder having formedin its side wall an opening, said opening being ada ted to receive aspark plug; a laterally projecting solid wall integral spark plug coolerextension formed on said cylinder around said opening, said extensionhaving an overall length substantially coextensive with the rojectinglength of the spark plug when Etted in said opening; and fins forcooling said c linder and said extension formed integral y therewith andwith each other upon the exterior wall of said cylinder and saidextension respectively, said fins throughout a portion of their lengthbeing extended lengthwise of said extension.

2. In an air cooled internal combustion engine; a cylinder having formedin its side wall an opening, said opening being adapted to receive aspark plug; a laterally projecting solid wall integral spark plug coolerextension formed on said cylinder around said opening, said extensionhaving an overall length substantially coextensive with the rojectinglength of the spark lug when tted in said opening; and fins or lcoolingsaid c linder and said extension formed integrally therewith and witheach other upon the exterior wall of said cylinder and said extensionrespectively, said fins throughout a portion of their lenglth beingextended uninterruptedly across t e top of said cylinder and throu houtthe remaining portion of their lengt being extended lengthwise of saidextension.

3. In an air cooled internal combustion engine; a cylinder having formedin its slde wall an opening, said opening being adapted to receive aspark plug; a laterally projecting solid wall integral spark plug coolerextension formed on said cylinder around said opening, said extensionhaving an overall length substantially coextensive with the projectinglength of the spark plug when fitted in said opening; and fins forcooling said cylinder and said extension formed integrally therewith andwith each other upon the exterior wall of said cylinder and said exvtension respectively, said fins throughout a 4portion of their lengthbeing extended substantially uninterruptedly circumferentially aroundsaid cylinder and throughout the remaining portion of their length beingextended lengthwise of said extension.

4. In an air cooled internal combustion engine; a cylinder havingopenings formed in its forward wall and in its rearward wallrespectively, each said opening being adapted to receive a spark plug;solid wall integral spark plug cooler extensions formed on saidcylinder, one each around each said opening to project laterally outfrom said cylinder at substantially diametrically opposite points, eachsaid extension having an overall len h substantially coextensive withthe projectmg length of its associated spark plug; and fins for coolingsaid cylinder and both said extensions formed integrally therewith andwith each other, said fins being extended substantially uninterrllptedlyacross the top of said cylinder and lengthwise of said extensions torespectively terminate at or near the. outer extension ends.

5. In an air cooled internal combustion engine; a cylinder havingopenings formed in its forward wall and in its rearward wallrespectively, each said opening being adapted to receive a spark plug;solid wall integral spark plug cooler extensions formed on saidcylinder, one each around each said opening to project 'laterally outfrom said cylinder at substantially diametrically opposite points, eachsaid extension having an overall length substantially coextensive withthe projectlng length of its associated spark plug; and fins for coolingsaid cylinder and both said extensions formed integrally there` i withand with each other, said fins being extended substantiallyuninterruptedly circumferentially around said cylinder and lengthwise ofsaid extensions to respectively terminate at or near the outer extensionends.

In testimony whereof I ,hereunto alx my

